Effects of nitrogen fertilization on fine root biomass and morphology of ash (Fraxinus mandshurica) and larch (Larix gmelinii) by using Ingrowth core approach

• 1、College of Forestry, Northeast Forestry University
• 2、 College of Horticulture and Forestry Science,Huazhong agricultural university

Abstract：Fine root biomass plays an important role in carbon cycling of forest ecosystem, and its morphology (e.g., diameter, length and specific root length) is one of major factors which affect absorbing function. However, fine root biomass and morphology are generally controlled by soil resource availability. In this paper, responses of fine root biomass and morphology to nitrogen (N) fertilization was studied at Maoershan Experiment Station by using ingrowth core approach during 2003 and 2004. We obtained fine root samples, separating different branch orders, in ash (Fraxinus mandshurica) and larch (Larix gmelinii) plantations. The results showed that N fertilization decreased fine root biomass in the first three order roots in both plantations. The diameter from the second to fourth order roots for ash and the third 3 for larch were increased after N fertilized, meanwhile, SRL in the first four order roots for ash and the first order roots for larch were significant decreased (p<0.05), however, root length was not significant changed. In contrast to control, root tissue N concentration of the first two order roots for ash was significant higher (p<0.05) in fertilized treatment, but no changed in larch roots. These results suggested that fine root biomass, morphology and tissue N were correlated with soil resource availability; however, the responses of two species to N fertilized were differed in this study.

Keywords： Fraxinus mandshurica Larix gmelinii nitrogen fertilization fine root biomass fine root morphology